The GTO has no real sensor for ambient temp. It has an "IAT" intake air temp reading, which can be somewhat improved upon by changing the IAT sensor to the "Omega Thermistor" or "Vector Engineering" kit.

My Gentex mirror with gompass has an actual Ambient temp sensor though. If you do it right, you can get running IATs within 6°F of ambient : and I am measuring with Omega right in front of the TB.

Have started scanning my car and the ambient always seems to go WAY higher then actual temps. Hell drive home tonight it was still showing 88 degrees and it was 40 outside.

Quote:

Originally Posted by Wang...

Ambient if you are using HP Tunas, is intake air temp, I am guessing.

The GTO has no real sensor for ambient temp. It has an "IAT" intake air temp reading, which can be somewhat improved upon by changing the IAT sensor to the "Omega Thermistor" or "Vector Engineering" kit.

My Gentex mirror with gompass has an actual Ambient temp sensor though. If you do it right, you can get running IATs within 6°F of ambient : and I am measuring with Omega right in front of the TB.

Correct, the ambient temp is a calculated or estimated value produced by the ECU based on IAT. On a "cold" start, ambient temp is assigned IAT temp and is modified as you drive. If your ambient temp is showing 88° on a 40° day/night, your intake system sucks like the factory air box or a K&N.

I worked over a Volant intake several years ago, insulating the box and MAF and isolating the air source to lower IAT's. Before my work I had sky high ambient temps like you, after I was done, ambient temps displayed were down to around 6° above actual ambient. After I switched over to a Vararam I insulated and sealed up to the hood, my IAT's are now equal to actual ambient and my displayed ambient is 6° below actual ambient.

Correct, the ambient temp is a calculated or estimated value produced by the ECU based on IAT. On a "cold" start, ambient temp is assigned IAT temp and is modified as you drive. If your ambient temp is showing 88° on a 40° day/night, your intake system sucks like the factory air box or a K&N.

I worked over a Volant intake several years ago, insulating the box and MAF and isolating the air source to lower IAT's. Before my work I had sky high ambient temps like you, after I was done, ambient temps displayed were down to around 6° above actual ambient. After I switched over to a Vararam I insulated and sealed up to the hood, my IAT's are now equal to actual ambient and my displayed ambient is 6° below actual ambient.

Cliffnotes:
Your CAI sucks hard.

Well the thing is my Ambient ends up the same as my IATs typically. Working on the intake. Not so easy with the Maggie. Even with the best intake you are not getting ambient IATs with a Maggie. They produce too much heat.

Try looking at ambient after the car has been sitting overnight and not getting hit with direct sunlight. It should read the same as actual temperature +- a few degrees. If not, the sensor itself might be bad, or the connector corroded.

Try looking at ambient after the car has been sitting overnight and not getting hit with direct sunlight. It should read the same as actual temperature +- a few degrees. If not, the sensor itself might be bad, or the connector corroded.

87LC2, I have the Vararam and insulated it just like yours. When I start the IAT and ambient are the same. If I stop at a light or after 10 minutes of driving the IAT will be 5-7 degrees above ambient(readings from Aeroforce gauge). Is that the best I can do? I don't have the IATRK but I was thinking about getting a used one. I don't know what the actual ambient is when I'm driving.

87LC2, I have the Vararam and insulated it just like yours. When I start the IAT and ambient are the same. If I stop at a light or after 10 minutes of driving the IAT will be 5-7 degrees above ambient(readings from Aeroforce gauge). Is that the best I can do? I don't have the IATRK but I was thinking about getting a used one. I don't know what the actual ambient is when I'm driving.

If I stop at a light for a minute or two, my IAT's will creep up a couple degrees, a few seconds after I leave the traffic light I'm back down to ambient. When I go past a Bank with the thermometer out front, my IAT's will match the thermometer. I've been a degree below or above some bank signs, but if I'm not jammed up in traffic I'm at ambient.

Stock IAT in the MAF.

I also noticed if I'm at a light with a tail wind, the IAT's will climb a little faster, if I have a head wind, they might not climb at all during the traffic light stop.

Heavy bumper to bumper traffic will add heat faster, and following a car at cruising speed after sitting in traffic will slow cool down. When the fans kick on, they like to force air out the corners of the hood scoops and it gets drawn back into the intake. I haven't tried sealing the vararam tray gap in the scoops yet as the heat isn't that bad over all, but it is a place where radiator heat gets into the vararam tray.

I was able to get my insulated Volant down to 5-7° above ambient.

Note:
At cruising speed, the ambient temp displayed on a scan tool like the Dashhawk will default to 5-7° below IAT. So that's why my ambient displayed is lower than actual ambient. The calculated ambient value is a little lower than the measured IAT value, obviously in the programming.

I followed the temps closely on my way home from work. The IAT was the same or 2 degrees above ambient for awhile. Then the ambient temperature dropped about 4 degrees and the IAT stayed the same or down 2 degrees. The difference was 4-6 degrees for the next 1/2 hour. When I got home I measured the outside air and it was 4 degrees above what the ambient was with the aeroforce. Which means the IAT was at actual ambient or 2 degrees above.

So, it seems to me the ambient stays correct for awhile then for some reason it drops below the actual outside temperature and stays lower. I kind of think that when I start driving I got onto the highway pretty quick and kept moving for a while. Then after I stopped at a few lights the IAT changed the way it was measured and lowered itself about 4 degrees below actual outside temp.

I used to notice this before but thought it was just that outside air temp changing as I went through different areas.

So overall, I think I have the vararam insulated fairly well. I just am curious why the ambient changes when the outside temp doesn't change.

Note:
At cruising speed, the ambient temp displayed on a scan tool like the Dashhawk will default to 5-7° below IAT. So that's why my ambient displayed is lower than actual ambient. The calculated ambient value is a little lower than the measured IAT value, obviously in the programming.

Before I did any insulation work, the displayed ambient would be higher than actual ambient, now it is lower. Like I said, the ambient temp display is a calculated or assumed value based on IAT readings. The better your intake system works, the lower your displayed ambient will be.

With my insulated Volant, my lowest displayed ambient would be actual ambient or a degree higher. With my insulated Vararam, displayed ambient is consistently below actual ambient. I vaguely remember back to 2006 with my stock air intake and ambient was more than 10° above actual.

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